衰減性全反射(ATR)是一種研究表面或介面光學性質非常靈敏的量測方法，ATR圖譜只反映出介面的特性，與金屬或介電物質的內部無關。若介面狀態發生變化，如介面增加的粗糙度、吸附了其他分子以及形成過渡層等，均會使得ATR圖譜的共振峰角度、寬度及峰值產生改變。近年來已有多項實驗證實，可以在金屬-真空、金屬-介電物質、介電物質-真空、金屬-液體及介電物質-液體等介面上均能有效測量。在應用方面，ATR因其分析方便、快速、檢測靈敏度高、無破壞性以及能得到測量位置的分子結構等特點，極大地減化了一些特殊樣品的測試，已成為分析物質表面結構的有力工具與手段。
二維材料來說由於其厚度最多僅有數個原子層，就可以得到均勻的載流子濃度調製，從而可能觀察到新的現象。另外，二維材料表面的化學吸附特性可以使其成為敏感的氣體分子探頭和生物探測傳感器。
自2004年發現以來，石墨烯因為具有獨特的二維結構使它在傳感器領域一直被寄予厚望，巨大的表面積使它對周圍的環境非常敏感。即使是一個氣體分子吸附或釋放都可以檢測到，當一個氣體分子被吸附於石墨烯表面時，吸附位置會發生電阻的局域變化，石墨烯的高電導率能夠偵測這微小的電阻變化。石墨烯的感測系統值得深入研究，因為它的整個區域能夠與周圍的氣體相互作用，使石墨烯成為氣體檢測的超靈敏材料 。然而，石墨烯和吸附分子之間的相互作用機制特別依賴於每種目標化學物質。在現有多樣氣體中，氨（NH3）因其對工業應用的重要性而被廣泛研究用於石墨烯基感測器。從理論方面來說，從NH3轉移到石墨烯的電荷取決於NH3分子的取向。而電場、基板摻雜、化學功能化和表面裝飾等其他參數也會影響氨的檢測。此外，使用微孔表面等基底工程能夠顯著提高石墨烯感測特性。基板，溫度和NH3濃度的影響之機制，需要進一步的理論和實驗研究。
研究顯示，NH3吸附通常會導致石墨烯的n型摻雜。與其他電子供體分子如CO相比，NH3是最大的電子供體之一，具有大量的電子轉移到石墨烯（0.03e。至於NH3吸附在石墨烯的方式與位置，透過density function theory (DFT)的計算，在缺陷處有較低能量造成吸附。然而對於2D材料而言，氣體分子吸附應該是以凡德瓦力(Van de Waals force)形式的物理吸附來主導。這與2D材料或是石墨烯的表面品質息息相關，如何進一步判定缺陷吸 附(包含物理及化學吸附)或是單純凡德瓦力物理吸附，這在分析工作是件挑戰。
ATR實驗的結果將透過電場的漸逝波來反應金屬薄膜及石墨烯上的氣體吸附與背景氣體折射率的訊息。透過ATR曲線中固定角度的高靈敏響應，可以觀察到不同氣體(Ar, O2, CO, NH3)的吸附現象。就不同氣體的特性來分析石墨烯吸附方式，藉此來分析不同氣體在石墨烯的吸附機制。此外，這一個工作亦可以提供石墨烯在表面電漿共振實驗的應用。

Attenuated Total Reflection (ATR) is a highly sensitive measurement method used to study the optical properties of surfaces or interfaces. Since its discovery in 2004, graphene has been highly anticipated in the field of sensors due to its unique two-dimensional structure, making it highly sensitive to the surrounding environment. Even the adsorption or release of a gas molecule can be detected.
This paper proposes combining graphene to enhance the capability of ATR measurement for gas adsorption. We transferred CVD graphene onto a gold film and observed the adsorption phenomena of different gases (N2, Ar, O2, CO, NH3) through the high-sensitivity response of the fixed-angle ATR curve. The results confirm that incorporating graphene enhances sensitivity to various gases by approximately 200%.

[1 ]AGBONLAHOR, O. G. et al. "Adsorbed Molecules as Interchangeable Dopants and Scatterers with a Van der Waals Bonding Memory in Graphene Sensors". ACS Sensors, v. 5, n. 7, p. 2003-2009, jul. 2020.
[2 ]CADORE, A. R. et al. "Enhancing the response of NH3 graphene-sensors by using devices with different graphene-substrate distances". Sensors and Actuators, B: Chemical, v. 266, p. 438-446, aug. 2018.
[3 ]STOLLER, M. D. et al. "Graphene-Based Ultracapacitors". Nano Letters, v. 8, n. 10, p. 3498-3502, oct. 2008.
[4 ]LEENAERTS, O.; PARTOENS, B.; PEETERS, F. M. "Adsorption of H2O, NH3, CO, NO2, and NO on graphene: A first-principles study". Physical Review B, v. 77, n. 12, p. 125416, mar. 2008.
[5 ]BOHM, D.; GROSS, E. P. "Theory of Plasma Oscillations. A. Origin of Medium-Like Behavior". Physical Review, v. 75, n. 12, p. 1851-1864, jun. 1949.
[6 ]BOHM, D.; GROSS, E. P. "Theory of Plasma Oscillations. B. Excitation and Damping of Oscillations". Physical Review, v. 75, n. 12, p. 1864-1876, jun. 1949.
[7 ]PINES, D. "Collective Energy Losses in Solids". Reviews of Modern Physics, v. 28, n. 3, p. 184-198, jul. 1956.
[8 ]RITCHIE, R. H. "Plasma Losses by Fast Electrons in Thin Films". Physical Review, v. 106, n. 5, p. 874-881, jun. 1957.
[9 ]HOPFIELD, J. J. "Theory of the Contribution of Excitons to the Complex Dielectric Constant of Crystals". Physical Review, v. 112, n. 5, p. 1555-1567, dec. 1958.
[10 ]MACKAY, T. G.; LAKHTAKIA, A. "Electromagnetic anisotropy and bianisotropy: a field guide". [S.l.]: World Scientific, 2010.
[11 ]TURBADAR, T. "Complete Absorption of Light by Thin Metal Films". Proceedings of the Physical Society, v. 73, n. 1, p. 40-44, jan. 1959.
[12 ]TURBADAR, T. "Complete Absorption of Plane Polarized Light by Thin Metallic Films". Optica Acta: International Journal of Optics, v. 11, n. 3, p. 207-210, jul. 1964.
[13 ]OTTO, A. "Excitation of Nonradiative Surface Plasma Waves in Silver by the Method of Frustrated Total Reflection". [S.l.], p. 398-410. 1968.
[14 ]KRETSCHMANN, E.; RAETHER, H. "Notizen: Radiative Decay of Non Radiative Surface Plasmons Excited by Light". Zeitschrift für Naturforschung A, v. 23, n. 12, p. 2135-2136, dec. 1968.
[15 ]FAHRENFORT, J. "Attenuated total reflection". Spectrochimica Acta, v. 17, n. 7, p. 698-709, jan. 1961.
[16 ]WOOD, R. W. "On a Remarkable Case of Uneven Distribution of Light in a Diffraction Grating Spectrum". Proceedings of the Physical Society of London, v. 18, n. 1, p. 269-275, jun. 1902.
[17 ]WOOD, R. W. "XLII. On a remarkable case of uneven distribution of light in a diffraction grating spectrum". The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, v. 4, n. 21, p. 396-402, sep. 1902.
[18 ]POLO, J. A.; MACKAY, T. G.; LAKHTAKIA, A. "Surface Waves". Electromagnetic Surface Waves, p. 1-36, jan. 2013.
[19 ]陳曄. 利用衰減式全反射方式探討二氧化釩表面與氧氣反應機制, 2012.
[20 ]GUO, J.; ZHU, Z.; DENG, W. "Small-angle measurement based on surface-plasmon resonance and the use of magneto-optical modulation". [S.l.]. 1999.
[21 ]GUPTA, B. D.; SHARMA, A. K. "Sensitivity evaluation of a multi-layered surface plasmon resonance-based fiber optic sensor: a theoretical study". Sensors and Actuators B: Chemical, v. 107, n. 1, p. 40-46, may. 2005.
[22 ]LEENAERTS, O.; PARTOENS, B.; PEETERS, F. M. "Adsorption of H2O, NH3, CO, NO2, and NO on graphene: A first-principles study". Physical Review B, v. 77, n. 12, p. 125416, mar. 2008.
[23 ]LIN, X.; NI, J.; FANG, C. "Adsorption capacity of H2O, NH3, CO, and NO 2 on the pristine graphene". Journal of Applied Physics, v. 113, n. 3, jan. 2013.
[24 ]LEE, C. et al. "Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene". Science, v. 321, n. 5887, p. 385-388, jul. 2008.
[25 ]TIAN, W.; LIU, X.; YU, W. "Research Progress of Gas Sensor Based on Graphene and Its Derivatives: A Review". Applied Sciences, v. 8, n. 7, p. 1118, jul. 2018.
[26 ]WEITZ, R. T.; YACOBY, A. "Graphene rests easy". Nature Nanotechnology, v. 5, n. 10, p. 699-700, oct. 2010.
[27 ]NAIR, R. R. et al. "Fine Structure Constant Defines Visual Transparency of Graphene". Science, v. 320, n. 5881, p. 1308-1308, jun. 2008.
[28 ]LEE, C. et al. "Elastic and frictional properties of graphene". physica status solidi (b), v. 246, n. 11-12, p. 2562-2567, dec. 2009.
[29 ]FRANK, I. W. et al. "Mechanical properties of suspended graphene sheets". Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, v. 25, n. 6, p. 2558, 2007.
[30 ]MOROZOV, S. V.; NOVOSELOV, K. S.; GEIM, A. K. "Electron transport in graphene". Physics-Uspekhi, v. 51, n. 7, p. 744-748, jul. 2008.
[31 ]SRUTI, A. N.; JAGANNADHAM, K. "Electrical Conductivity of Graphene Composites with In and In-Ga Alloy". Journal of Electronic Materials, v. 39, n. 8, p. 1268-1276, aug. 2010.
[32 ]BALANDIN, A. A. et al. "Superior Thermal Conductivity of Single-Layer Graphene". Nano Letters, v. 8, n. 3, p. 902-907, mar. 2008.
[33 ]NAIR, R. R. et al. "Universal Dynamic Conductivity and Quantized Visible Opacity of Suspended Graphene", mar. 2008.
[34 ]KUILA, T. et al. "Chemical functionalization of graphene and its applications". Progress in Materials Science, v. 57, n. 7, p. 1061-1105, sep. 2012.
[35 ]JIANG, Y. et al. "Graphene Oxides in Water: Correlating Morphology and Surface Chemistry with Aggregation Behavior". Environmental Science & Technology, v. 50, n. 13, p. 6964-6973, jul. 2016.
[36 ]JIANG, Y. et al. "Graphene oxides in water: assessing stability as a function of material and natural organic matter properties". Environmental Science: Nano, v. 4, n. 7, p. 1484-1493, 2017.
[37 ]KATSNELSON, M. I. "Graphene: carbon in two dimensions". Materials Today, v. 10, n. 1-2, p. 20-27, jan. 2007.
[38 ]TIAN, W. et al. "A Review of Graphene on NEMS". Recent Patents on Nanotechnology, v. 10, n. 1, p. 3-10, mar. 2016.
[39 ]SUK, J. W. et al. "Transfer of CVD-Grown Monolayer Graphene onto Arbitrary Substrates". ACS Nano, v. 5, n. 9, p. 6916-6924, sep. 2011.
[40 ]LI, X. et al. "Evolution of Graphene Growth on Ni and Cu by Carbon Isotope Labeling". Nano Letters, v. 9, n. 12, p. 4268-4272, dec. 2009.
[41 ]PENG, Z. et al. "Toward the Synthesis of Wafer-Scale Single-Crystal Graphene on Copper Foils (vol 6, pg 9110, 2012)". ACS NANO, v. 7, n. 1, p. 875, 2013.
[42 ]LAND, T. A. et al. "STM investigation of single layer graphite structures produced on Pt(111) by hydrocarbon decomposition". Surface Science, v. 264, n. 3, p. 261-270, mar. 1992.
[43 ]REINA, A. et al. "Large Area, Few-Layer Graphene Films on Arbitrary Substrates by Chemical Vapor Deposition". Nano Letters, v. 9, n. 1, p. 30-35, jan. 2009.
[44 ]MARCHINI, S.; GÜNTHER, S.; WINTTERLIN, J. "Scanning tunneling microscopy of graphene on Ru(0001)". Physical Review B, v. 76, n. 7, p. 075429, aug. 2007.
[45 ]CORAUX, J. et al. "Structural Coherency of Graphene on Ir(111)". Nano Letters, v. 8, n. 2, p. 565-570, feb. 2008.
[46 ]MORIYAMA, S. et al. "Coupled Quantum Dots in a Graphene-Based Two-Dimensional Semimetal". Nano Letters, v. 9, n. 8, p. 2891-2896, aug. 2009.
[47 ]SOMANI, P. R.; SOMANI, S. P.; UMENO, M. "Planer nano-graphenes from camphor by CVD". Chemical Physics Letters, v. 430, n. 1-3, p. 56-59, oct. 2006.
[48 ]CHEN, F. et al. "Electrochemical Gate-Controlled Charge Transport in Graphene in Ionic Liquid and Aqueous Solution". Journal of the American Chemical Society, v. 131, n. 29, p. 9908-9909, jul. 2009.
[49 ]LI, X. et al. "Large-Area Synthesis of High-Quality and Uniform Graphene Films on Copper Foils". Science, v. 324, n. 5932, p. 1312-1314, jun. 2009.
[50 ]COPEL, M. et al. "Surfactants in epitaxial growth". Physical Review Letters, v. 63, n. 6, p. 632-635, aug. 1989.
[51 ]BOROVIKOV, V.; ZANGWILL, A. "Step-edge instability during epitaxial growth of graphene from SiC(0001)". Physical Review B, v. 80, n. 12, p. 121406, sep. 2009.
[52 ]BERGER, C. et al. "Ultrathin Epitaxial Graphite:  2D Electron Gas Properties and a Route toward Graphene-based Nanoelectronics". The Journal of Physical Chemistry B, v. 108, n. 52, p. 19912-19916, dec. 2004.
[53 ]ZHU, Y. et al. "Graphene and Graphene Oxide: Synthesis, Properties, and Applications". Advanced Materials, v. 22, n. 35, p. 3906-3924, sep. 2010.
[54 ]STAUDENMAIER, L. "Verfahren zur darstellung der graphitsäure". Berichte der deutschen chemischen Gesellschaft, v. 31, n. 2, p. 1481-1487, 1898.
[55 ]HIRATA, M. et al. "Thin-film particles of graphite oxide 1:High-yield synthesis and flexibility of the particles". Carbon, v. 42, n. 14, p. 2929-2937, 2004.
[56 ]BABURIN, I. A. et al. "Hydrogen adsorption by perforated graphene". International Journal of Hydrogen Energy, v. 40, n. 20, p. 6594-6599, jun. 2015.
[57 ]GANESAN, A.; SHAIJUMON, M. M. "Activated graphene-derived porous carbon with exceptional gas adsorption properties". Microporous and Mesoporous Materials, v. 220, p. 21-27, jan. 2016.
[58 ]ZHANG, L. et al. "Porous 3D graphene-based bulk materials with exceptional high surface area and excellent conductivity for supercapacitors". Scientific Reports, v. 3, n. 1, p. 1408, mar. 2013.
[59 ]. "XIV. Researches on the refraction, dispersion, and sensitiveness of liquids". Philosophical Transactions of the Royal Society of London, v. 153, p. 317-343, dec. 1863.
[60 ]PECK, E. R.; KHANNA, B. N. "Dispersion of Nitrogen*". Journal of the Optical Society of America, v. 56, n. 8, p. 1059, aug. 1966.
[61 ]PECK, E. R.; FISHER, D. J. "Dispersion of Argon". Journal of the Optical Society of America, v. 54, n. 11, p. 1362, nov. 1964.
[62 ]. "info getting lost lost in the gutter on page 219 - I. On the refraction and dispersion of the halogens, halogen acids, ozone, steam, oxides of nitrogen and ammonia". Philosophical Transactions of the Royal Society of London. Series A, Containing Papers of a Mathematical or Physical Character, v. 213, n. 497-508, p. 1-26, jan. 1914.
[63 ]. "On the refraction and dispersion of carbon dioxide, carbon monoxide, and methane". Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, v. 97, n. 683, p. 152-159, apr. 1920.
[64 ]ZHANG, J.; LU, Z. H.; WANG, L. J. "Precision refractive index measurements of air, N_2, O_2, Ar, and CO_2 with a frequency comb". Applied Optics, v. 47, n. 17, p. 3143, jun. 2008.
[65 ]MORENO-BÁRCENAS, A. et al. "Graphene Synthesis Using a CVD Reactor and a Discontinuous Feed of Gas Precursor at Atmospheric Pressure". Journal of Nanomaterials, v. 2018, p. 1-11, 2018.
[66 ]沈郡豪. 低維度FAPbI3量子點/石墨烯異質結構紫外光感測器, nov. 2022.
[67 ]JOHNSON, P.; CHRISTY, R. "Optical constants of transition metals: Ti, V, Cr, Mn, Fe, Co, Ni, and Pd". Physical Review B, v. 9, n. 12, p. 5056-5070, jun. 1974.
[68 ]JOHNSON, P. B.; CHRISTY, R. W. "Optical Constants of the Noble Metals". Physical Review B, v. 6, n. 12, p. 4370-4379, dec. 1972.
[69 ]EL-SAYED, M. A. et al. "Optical Constants of Chemical Vapor Deposited Graphene for Photonic Applications". Nanomaterials, v. 11, n. 5, p. 1230, may. 2021.
[70 ]KRYACHKO, E. S.; REMACLE, F. "The gold-ammonia bonding patterns of neutral and charged complexes Aum0±1–(NH3)n. I. Bonding and charge alternation". The Journal of Chemical Physics, v. 127, n. 19, p. 194305, nov. 2007.
[71 ]SCHEDIN, F. et al. "Detection of individual gas molecules adsorbed on graphene". Nature Materials, v. 6, n. 9, p. 652-655, sep. 2007.
[72 ]B JOHNSON, P. P. "Optical constants of transition metals". [S.l.]. 1974.